JP2010161398A - Superconducting magnet protective unit - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a superconducting magnet protective unit, capable of improving the operability and reducing the heat generated, at excitation or degaussing. <P>SOLUTION: The superconducting magnet protective unit has a superconducting magnet unit 6, in which identical number of superconducting coils 1 are connected, in series on each of right and left sides so as to be located to the right and the left, opposite to each other; and a power supply 10 connected between start end terminals of each superconducting coil at a start end position in the superconducting coils connected in series on each of the left and the right sides; and a short-circuit formed between end terminals of each superconducting coil at an end terminal position in the superconducting coils connected in series on each of the left and the right sides. Moreover, the superconducting magnet protective unit has an emergency demagnetization protective resistor 8a, inserted between every connection midpoints of both terminals of the superconducting coils 1 opposing the left and the right, a series circuit of a loop discharge tube 9al and a compulsive demagnetization protective resistor 8b, which is inserted between every connection midpoints and the terminal of any one of the right or the left of the superconducting coil, and a loop discharge tube 9ar, inserted between each connection midpoints and the terminal of the other of the right or the left of the superconducting coil. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a superconducting magnet protection device for a superconducting magnet device using a superconducting coil mounted on a magnetic levitation train using a magnetic field.

  A schematic structure of a magnetic levitation train vehicle using a magnetic field is as shown in FIG. The superconducting magnet device 6 containing the superconducting coil 1 and the permanent current switch is mounted on both the left and right sides under the floor of the vehicle 3 and faces the propulsion coil 4 and the levitation guide coil 5 provided on the left and right sides on the ground side. The vehicle 3 of the magnetic levitation train having such a structure is propelled by the electromagnetic force of the superconducting magnet device 6 and the propulsion coil 4, and a levitation force is generated by the induced current of the superconducting magnet device 6 and the levitation guide coil 5 associated therewith. At the same time, the guide force acts so as to always be in the center position with respect to the left and right displacement.

  The superconducting magnet device 6 of such a magnetic levitation train employs a circuit configuration as shown in FIGS. 6 to 8 as a protection device against quenching of the superconducting coil 1. The superconducting magnet protection device shown in FIG. 6 has a series circuit of a diode 7 and a protective resistor 8 connected in parallel to each of the superconducting coils 1 on both the left and right sides. The protective device shown in FIG. 7 is a circuit that forcibly demagnetizes only the superconducting coil 1 at both ends of the side closer to and far from the excitation demagnetizing power source 10 using the discharge tube 9 having the configuration described in Japanese Patent No. 2708678. The superconducting coil 1 at the center is the same as the circuit configuration shown in FIG. 6. The superconducting magnet protection circuit shown in FIG. 8 forcibly demagnetizes all the superconducting coils 1 of the superconducting magnet device 6 with a circuit that performs emergency demagnetization using loop discharge tubes 9a, 9b, 9c, and 9d having different discharge starting voltages. The circuit configuration also serves as a circuit. Here, for the loop discharge tubes 9, 9a, 9b,..., Etc., the “switch for superconducting magnet protection circuit” of the invention of Japanese Patent No. 2708678 is used.

  In such a conventional superconducting magnet protection device, when one of the superconducting coils 1 is quenched, the heater of the permanent current switch 2 of the opposite superconducting coil 1 is turned on for emergency demagnetization. In addition, even when there is no excitation demagnetizing power source 10, the protective resistance value is selected so that forced demagnetization can be performed by turning on the heater of the permanent current switch 2 without quenching the superconducting coil 1.

  However, the superconducting magnet protection device having any of the above-described configurations has the following problems. In the superconducting magnet protection device shown in FIG. 6, since the protective resistance value is set so as not to cause quenching due to forced demagnetization, the current of the superconducting coil 1 on the opposite side is compared with the rapid current decay of the superconducting coil 1 quenched during emergency demagnetization. Attenuation was slow, and there was a problem that the abnormal left-right force could not be reduced during emergency demagnetization due to quenching of the opposing superconducting coil.

  Further, in the superconducting magnet protection device shown in FIG. 7, when simultaneous quenching of the four coils of the superconducting coil 1 is assumed, the current decay of the opposing coil with respect to the quenched central coil is slow due to the circuit configuration of the central coil. There was a problem that the effect of reducing the abnormal left-right force during emergency demagnetization due to quenching of the side coil could not be fully expected.

  Further, in the superconducting magnet protection device shown in FIG. 8, when the simultaneous quenching of the four coils of the superconducting coil 1 is assumed, it is possible to reduce the abnormal left-right force at the time of emergency demagnetization by quenching the opposing coil, but the resistance value Depending on the selection and inductance of the superconducting coil, coil resistance at the time of transition to normal conduction, etc., there is a problem that the generated voltage may exceed the allowable withstand voltage of the device. In addition, there is a problem that current shunting to the protective resistor occurs in the superconducting coil on one side with protective resistance during excitation and demagnetization, and the rated current holding time is required until the coil current reaches the rated current, resulting in poor operability. . Furthermore, there is a problem that the heat penetration amount and the heat load increase with an increase in the heat capacity of the current leads and an increase in the excitation and demagnetization loss.

  The present invention has been made in view of such conventional problems, and an object thereof is to provide a superconducting magnet protection device capable of improving operability and reducing heat generation during excitation and demagnetization.

  In the superconducting magnet protection device according to the first aspect of the present invention, the same number of superconducting coils are connected in series on the left and right so as to face each other on the left and right, and the superconductivity at the start position of the superconducting coils connected in series on each of the left and right A superconducting magnet device in which a power source is connected between the start terminals of each of the coils, and the terminal terminals of the superconducting coils at the terminal positions of the superconducting coils connected in series in each of the left and right are short-circuited; Loop discharge inserted between each of the terminals of the superconducting coil facing each other and the emergency demagnetization protection resistor inserted between the terminals of the superconducting coils facing each other and the terminal of the superconducting coil on either the left or right side. A loop discharge tube inserted between a series circuit of a tube and a forced demagnetization protection resistor and between the connection midpoint and the terminal of the left or right superconducting coil It is made of.

  In the superconducting magnet protection device according to the first aspect of the present invention, the loop discharge tube exists between each terminal of the left and right superconducting coils facing each other and the midpoint of connection between them, so that the superconducting magnet protection device is generated only in one superconducting coil. Current shunting at the time of excitation and demagnetization of the protective resistor can be prevented, and it is not necessary to maintain the rated current by the power source and to energize the permanent current switch heater during this time, improving the operability of the power source at the time of excitation and demagnetization. Increment of heat load such as an increase in the heat capacity and loss of excitation and demagnetization due to heat generated by the permanent current switch heater can be reduced.

  In the superconducting magnet protection device according to the second aspect of the present invention, the same number of superconducting coils are connected in series on the left and right so as to oppose each other on the left and right, and the superconductivity at the start position of the superconducting coils connected in series on each of the left and right A superconducting magnet device in which a power source is connected between the start terminals of each of the coils, and the terminal terminals of the superconducting coils at the terminal positions of the superconducting coils connected in series in each of the left and right are short-circuited; An emergency demagnetization protection resistor inserted between the connection midpoints of both terminals of the opposing superconducting coils, and a loop discharge tube inserted between the connection midpoint and the terminals of the left and right superconducting coils, It consists of a series circuit with a forced demagnetization protection resistor.

  In the superconducting magnet protection device according to the second aspect of the present invention, the loop discharge tube, forced demagnetization protection resistance, and emergency demagnetization protection resistance are symmetrically connected to the left and right opposing superconducting coils. In addition to the above action, in the left and right superconducting coils, when a forced demagnetization protection resistor is inserted only in one superconducting coil, it is possible to prevent the voltage imbalance between the left and right coils that may occur when a quench occurs. The same voltage specifications can be adopted for the left and right components.

  The invention according to claim 3 is the superconducting magnet protection device according to claim 1 or 2, wherein the midpoint potential point is grounded via an earth resistor. In addition, the voltage at both ends can be fixed to 1/2 by splitting the generated voltage from the midpoint ground to both sides, and a margin can be secured for the withstand voltage of the superconducting coil and current lead device, and the protective resistance Can be increased and the abnormal left-right force of emergency demagnetization can be further reduced.

  According to the first aspect of the present invention, since there is a loop discharge tube between each of the terminals of the left and right opposing superconducting coils and the connection midpoint between them, the protective resistance generated only in one superconducting coil is reduced. Current shunting at the time of excitation demagnetization can be prevented, and it is not necessary to maintain the rated current by the power source and to energize the permanent current switch heater during this time, improving the operability of the power source at the time of excitation demagnetization, and the heat capacity of the current lead Thermal load increments such as increase and loss of excitation demagnetization due to heat generation of the permanent current switch heater can be reduced.

  According to the invention of claim 2, since the loop discharge tube, the forced demagnetization protection resistance, and the emergency demagnetization protection resistance are connected symmetrically with respect to the left and right opposing superconducting coils, the effect of the invention of claim 1 is achieved. In addition, in the left and right superconducting coils, when a forced demagnetization protection resistor is inserted only in one superconducting coil, it is possible to prevent the voltage imbalance between the left and right coils that can occur when quenching occurs. The same voltage specifications can be adopted for the constituent devices.

  According to the invention of claim 3, since the midpoint potential point of the protection device is grounded via the ground resistance, in addition to the effect of the invention of claim 1 or 2, the generated voltage is divided from the midpoint ground to both sides. By generating it, the voltage at both ends can be fixed to ½, a margin can be secured for the withstand voltage of the superconducting coil and the current lead device, and the set value of the protective resistance can be increased so that it can be used during emergency demagnetization. Abnormal left-right force can be further reduced.

1 is a circuit diagram of a first embodiment of the present invention. The circuit diagram of the 2nd Embodiment of this invention. The circuit diagram of the 3rd Embodiment of this invention. The circuit diagram of the 4th Embodiment of this invention. Sectional drawing which shows the structure of a general magnetic levitation train. The circuit diagram of a prior art example. The circuit diagram of another prior art example. The circuit diagram of other conventional examples.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. FIG. 1 shows a circuit configuration of a superconducting magnet protection device according to a first embodiment of the present invention. The superconducting magnet protection device according to this embodiment includes a superconducting coil 1 disposed on both the left and right sides, a permanent current switch 2, a loop discharge tube 9 inserted between terminals of the left and right superconducting coils 1 and forced demagnetization protection. It is composed of a series circuit with a resistor 8b and an emergency demagnetization protection resistor 8a connected in parallel between both terminals of each superconducting coil 1. Then, with respect to this superconducting magnet protection device, the circuit protection resistor 8p and the circuit protection are provided in parallel with the emergency demagnetization protection resistor 8a group between the terminal Cn outside the emergency demagnetization protection resistor 8a at the end position and the excitation demagnetization power source 10. A protection circuit 11 comprising a series circuit with the discharge tube 9p is connected.

  The resistance value of the circuit protection resistor 8p in the protection circuit 11 is selected such that the combined resistance of the parallel circuit with the emergency demagnetization protection resistor 8a group is equal to or less than a reference value. The circuit protection discharge tube 9p is selected to have a characteristic of starting discharge at the reference set voltage value.

  As the loop discharge tube 9, an all-loop discharge tube 9a, a 3/4 loop discharge tube 9b, a 1/2 loop discharge tube 9c, and a 1/4 loop discharge tube 9d are used, and these loop discharge tubes 9a to 9d are The discharge start voltage is gradually lower in proportion.

  Note that all of these loop discharge tubes 9, 9a,... Employ the “superconducting magnet protection circuit switch” according to the invention of Japanese Patent No. 2708678 as described in the prior art. The principle of the operation is that the internal electrodes are arranged in advance in a small distance in an inert gas, and the energy stored in the superconducting magnet is used during protection. The circuit is constructed, and then the circuit is constructed by melting the electrodes by arc heat during arc discharge and welding both electrodes, thereby shifting from the circuit configuration by arc discharge to the circuit configuration by welding of both electrodes. It is.

  In the superconducting magnet protection device of the above embodiment, the circuit protection resistor 8p and the circuit are connected in parallel to the protection device constituted by the emergency demagnetization protection resistor 8a, the forced demagnetization protection resistor 8b, and the loop discharge tubes 9a to 9d. A protection circuit 11 including a protection discharge tube 9p is provided in parallel, and the resistance value of the circuit protection resistor 8p is set so that the parallel combined resistance value with the protection resistor 8a group is equal to or less than a reference value. Since 9p is selected to start discharge at the reference voltage value, when an abnormal high voltage higher than the reference voltage value is generated, the circuit protection discharge tube 9p is discharged first, and the voltage can be controlled to be low by voltage sharing. It is. For this reason, it is possible to prevent a voltage exceeding the reference value from being generated.

  Next, a second embodiment of the present invention will be described with reference to FIG. In the superconducting magnet protection device according to the second embodiment, an emergency demagnetization protection resistor 8a is inserted between the connection midpoints of both terminals of the superconducting coil 1 facing each other on the left and right sides, and each connection midpoint and either the left or right side are connected. A series circuit of a loop discharge tube 9l and a forced demagnetization protection resistor 8b is inserted between the terminals of the superconducting coil 1 (the left side if the upper side is right and the lower side is left). The loop discharge tube 9r is inserted between the middle point and the terminal of the superconducting coil 1 on either the left or right side (right side here).

  For the loop discharge tubes 9r and 9l, all-loop discharge tubes 9ar and 9al, 3/4 loop discharge tubes 9br and 9bl, 1/2 loop discharge tubes 9cr and 9cl, and 1/4 loop discharge tubes 9dr and 9dl are used. These loop discharge tubes 9ar to 9dr; 9al to 9dl have discharge start voltages that are proportionally lower in order.

  In the superconducting magnet protection device of the second embodiment, the loop discharge tubes 9r and 9l are individually provided for the left and right superconducting coils 1 with respect to the circuit configuration of the first embodiment shown in FIG. Since it is a connected configuration, it is possible to prevent current shunting at the time of excitation demagnetization to the emergency demagnetization protection resistor 8a that occurs only in the superconducting coil 1 on the left and right sides, and the rated current that raises the coil current to the power supply current of the excitation demagnetization power source 10 Is not necessary, and it is not necessary to energize the heater of the permanent current switch 2 for the time until the shunting disappears, improving the operability of the superconducting magnet coil 1 and the excitation demagnetizing power source 10 during excitation and demagnetization, and the current. The thermal load increments such as increase in the heat capacity of the leads and loss of excitation and demagnetization due to the heat generated by the heater of the permanent current switch 2 are reduced.

  Next, a third embodiment of the present invention will be described with reference to FIG. The superconducting magnet protection device according to the third embodiment is further compared with the superconducting magnet protection device according to the second embodiment shown in FIG. Between the left and right sides, a series circuit of the loop discharge tube 9r and the forced demagnetization protection resistor 8r and a series circuit of the loop discharge tube 9l and the forced demagnetization protection resistor 8l are inserted symmetrically. In this configuration, an emergency demagnetization protection resistor 8a is connected between connection midpoints. The loop protection discharge tubes 9r, 9l include all loop discharge tubes 9ar, 9al, 3/4 loop discharge tubes 9br, 9bl, 1/2 loop discharge tube 9cr, as in the first and second embodiments. 9cl and 1/4 loop discharge tubes 9dr and 9dl are used.

  In the superconducting magnet protection device according to the third embodiment, a series circuit in which a forced demagnetization protection resistor and a loop discharge tube are paired is inserted into each of the left and right superconducting coils 1 individually. Similarly to the protection device of the second embodiment shown in FIG. 2, it is possible to prevent current shunting at the time of excitation / demagnetization to the emergency demagnetization protection resistor 8a that occurs only in the superconducting coil 1 on the left and right sides, thereby exciting the coil current. It is not necessary to maintain the rated current that is raised to the power supply current of the demagnetizing power source 10, and it is not necessary to energize the heater of the permanent current switch 2 until the shunt current disappears, and the superconducting magnet coil 1 and the excited demagnetizing power source during excitation demagnetization are eliminated. 10 is improved, and the thermal load increment such as the increase in the heat capacity of the current lead and the loss of excitation and demagnetization due to the heat generation of the heater of the permanent current switch 2 is reduced.

  In addition to this, since the circuit configuration is symmetrical, the forced demagnetization protection resistor 8b is inserted only in the superconducting coil 1 on one side as in the second embodiment shown in FIG. The difference in the generated voltage due to the difference in the coil occurrence due to quenching does not occur, and therefore, the right and left devices having the same voltage specifications can be adopted.

  Next, a fourth embodiment of the present invention will be described with reference to FIG. The superconducting magnet protection device according to the fourth embodiment is connected to the circuit middle point Ct via a ground resistance 8r of several k ohms with respect to the superconducting magnet protection device according to the first embodiment shown in FIG. It is characterized by that.

  In this way, the circuit midpoint Ct of the superconducting magnet protection device is grounded via the grounding resistor 8r, so that the generated voltage is divided and generated on both sides from the midpoint grounding point Ct, and the generated voltage at both ends is reduced by half. It is possible to secure the margin of the withstand voltage of the superconducting coil 1 and the current lead device, and it is possible to increase the set value of the protective resistance 8p to speed up the current attenuation, and thus emergency demagnetization. It is possible to further reduce the abnormal lateral force at the time.

  The present invention is not limited to the above-described embodiments, and the following configuration can also be adopted. In the second embodiment shown in FIG. 2 and the third embodiment shown in FIG. 3, the first terminal Cn between the outer ends of the superconducting coils 1 group and the excitation demagnetizing power source 10 are As in the embodiment, the protection circuit 11 including the circuit protection resistor 8p and the circuit protection discharge tube 9p can be connected in parallel. Thus, as in the first embodiment, when an abnormal high voltage higher than the reference voltage value is generated, the circuit protection discharge tube 9p is discharged first, and the voltage can be controlled to be low by voltage sharing. is there.

  Further, in each of the first embodiment shown in FIG. 1, the second embodiment shown in FIG. 2, and the third embodiment shown in FIG. 3, the fourth embodiment shown in FIG. Similarly to the embodiment, the circuit middle point Ct can be grounded via the grounding resistor 8r, whereby the generated voltage is divided and generated on both sides from the middle point ground point Ct, and the generated voltage at both ends is reduced by half. It is possible to secure the margin of withstand voltage of the superconducting coil 1 and the current lead device.

  Further, in the second embodiment shown in FIG. 2 and the third embodiment shown in FIG. 3, the circuit midpoint Ct together with the protection circuit 11 is provided in the same manner as the fourth embodiment shown in FIG. Thus, the same effects as those of the fourth embodiment can be obtained.

DESCRIPTION OF SYMBOLS 1 Superconducting coil 2 Permanent current switch 6 Superconducting magnet apparatus 8a, 8ar, 8al Emergency demagnetization protection resistance 8b, 8br, 8bl Forced demagnetization protection resistance 8p Circuit protection resistance 8r Earth resistance 9 Loop discharge tube 9a, 9ar, 9al All loop discharge tube 9b , 9br, 9bl 3/4 loop discharge tube 9c, 9cr, 9cl 1/2 loop discharge tube 9d, 9dr, 9dl 1/4 loop discharge tube 9p circuit protection discharge tube 10 excitation demagnetizing power source 11 protection circuit

Claims (3)

The same number of superconducting coils are connected in series on the left and right sides so as to face each other on the left and right, and a power source is connected between the starting end terminals of each of the superconducting coils at the starting end position of the superconducting coils connected in series on each of the left and right sides, A superconducting magnet device in which the terminal terminals of the superconducting coils at the terminal positions of the superconducting coils connected in series in each of the left and right are short-circuited, and
Emergency demagnetization protection resistor inserted between the connection midpoints of both terminals of the superconducting coil opposite to the left and right,
A series circuit of a loop discharge tube and a forced demagnetization protection resistor inserted between the connection midpoint and the terminal of either the left or right superconducting coil,
A superconducting magnet protection device comprising a loop discharge tube inserted between the connection midpoint and a terminal of either the left or right superconducting coil. The same number of superconducting coils are connected in series on the left and right sides so as to face each other on the left and right, and a power source is connected between the starting end terminals of each of the superconducting coils at the starting end position of the superconducting coils connected in series on each of the left and right sides, A superconducting magnet device in which the terminal terminals of the superconducting coils at the terminal positions of the superconducting coils connected in series in each of the left and right are short-circuited, and
Emergency demagnetization protection resistor inserted between the connection midpoints of both terminals of the superconducting coil opposite to the left and right,
A superconducting magnet protection device comprising a series circuit of a loop discharge tube and a forced demagnetization protection resistor inserted between the connection midpoint and the terminals of the left and right superconducting coils.   The superconducting magnet protection device according to claim 1 or 2, wherein the midpoint potential point is grounded via an earth resistance.

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